Electrical equalizer system.



W. COOPER.

ELECTRICAL EQUALIZER SYSTEM. APPLICATION FILED SEPT. 3,1907. RENEWED my20, 1910.

977,598. Patented -Dec. 6,1910.

WITNESSES:

, mv Mon zzaa/dw M ATTORNEY Patented 1m 6,1910,

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I INVENTOR v WITNESSES! if 631% ATTORNEY MAM mam nc w. 000mm. BLEOTBIOALEQUALIZBB SYSTEM. APYLIOATXOI TILED PT. 3, 1907. lBIEWli) IA! 20, 1010.

977 59 Patented Deg 6,1910.

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WITNESSES:

' IPIJVENTOR" %%@1% ATTORNEY mam mus, m: unn. lumnnn me w. COOPER.

' ELECTRICAL EQUALIZER SYSTEM. I APPLICATION FILED SEPT. 3, 1907.RENEWED KAY 20, 1910.

" 977,598. 'Patented Dec. 6, 1910.

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WITNESSES: mvamon ATTORNEY.

w COOPER.

ELECTRICAL EQUALIZEB SYSTEM. nwmou'xox r1121) SEPT. a, 1901. nnnwnn In20, 1910.

. 977,598, Patented Dec.6,1910.

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If E mx 1' WITNESSES: I INVENTOR W. COOPER.

ELECTRICAL EQUALIZBR SYSTEM.

APPLICATION FILED SEPT. 3, 1907. RENEWED MAY 20, 1910.

977,598. Patented Dec. 6,1910.

6 SHEETS-411E136.

WITNESSES: V INVENTOR MW W M ATTORNEY system is variable.

UNITED STATES arana. OFFICE,

WILLIAM COOPER," OF PITTSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSEELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRICAL EQU'ALIZE SYSTEM.

i Specification of Letters Patent.

Patented "Death1910.

Application filed September. 3, 1907, Serial No. 391,224, Renewed May20, 1910. Serial No. 562,526.

To all whom it may concern: I

Be it known that I, VILLIAM Coornn, a citizen of the'United States, and.,a resident of Pittsburg, in the county of Allegheny and State ofPennsylvania,'ha\-'e invented a new and useful Improvement in ElectricalEqualizer Systems, of which the following is a specification.

My invention relates to systems of electrical distribution, andparticularly to means for equalizing the load upon the generating orsupply station' when the load upon the invention is to provide SlII'lPlGand effect ve means that may be employed in connection with alternatingcur' The object jot; my

rent systems of any number of phases for absorbing or yielding energy inaccordance with variations in load upon the system, in such a mannerthat the loadupon the gen erating or supply station of the system mayremain substantially constant or may not exceed a predetermined value. 1

It hasheretofore been proposed to employ fly-wheels. or other deviceshaving considerable inertia, in systems of distribution that supplytranslating devices requiring widely varying amounts of power, andto sodrive the flywheels and. control their operation that the load upon thedistributing circuit Will remain substantially constant, regardless ofthe variations in the amount of power required by the translatingdevices.

In the present system, a dynamo-electric machine, that may operateeither as a motor or as a generator and to which a fly-wheel ismechanically coupled, is directly connected to the distributingcircuitwithout the intervention of a rotary cmiverter or other device, and thearrangement is such that but comparatively small and inexpensivemachines need be provided and only asingle equalizer set is necessaryfor equalize ing the load provided by av plurality ojt. translatingdevices.

The invention is especially adapted for use in connection withalternating current systems of dist ibution, and in its most usefulembodiment it comprises a plurality ot mechanically coupleddynalilo-electric machines,ot the commutator type, one for each phase ofthe system of distri-luition. a fiywheel being also coupled to the saidiuachines. Thearniatures of the machines are connected, respectively, tothe various phases A motive forces of the armatures may be nearly of thesame phases as the electromotive forces of the circuits to which theyare connected. The machines are caused to operate alternately as motorsand generators, by adjusting their field strengths, or otherwise, inaccordance with the variations in the load atllorded by the translatingdevices, energy being stored in the fly-wheel when operating themachines as motors and yielded for operating the machines'as generatorsin order to supply current to the system.

It is not only desirable that the armature electromotive forces shouldbe nearly'of the same phase as those of the circuits to which they areconnected, but also, under the most usual conditions, that the currentsin the armature circuits be of approximately the same phases-as theelectromotive forces of the circuits to which the armaturcs areconnected, and it is the specific object of the present invention toinsure this result under substantially all conditions of load andwhether the machines operate as motors or as generators. i

Figures 1, 2 and 3 ,of the accompanying drawings are diagrammatic viewsof three arrangements of the circuits of three-phase systems ofdistribution that embody my invention. Figs. -il-, 5, (3 and 7 arevector diagrams illustrating the phase relations of the currents andelectromotive forces in the systems shown in Figs. 1, 2 and 3. Fig. 8 adiagrammatic view of a two-phase system of distribution embodying theinvention, and Figs. 5) and 10 are vector diagrams illustrating thephase relations of the currents and elec'tromotive forces in the systemshown in l S, and Fig. 11 is a diagrammatic view of a single-phasesystem of distribution that embodies the invention.

In Fig. l, mechanically coupled armatures 1, 2 and 3 of three dynamo elcetrie machines of the commutator type ot'construction, are connected,respectively, betweenthc different pairs of conductors at, 5 and ('3 ofa three phase circuit that is supplied from a generator 7, or othersuitable source, the armatures being provided with large masses, or afly-wheel 8 being coupled thereto, in order that therotatable.systen1,n1ay possess considerable inertia. Also connectedbetween the difl'erent pairs of conductors of the supply circuit arethree sub-divided delta-connected windings 9, l0 and 11 of athree-phase. transformer. the points of subdivision of the respectivewindings being connected to sets of stationary contact terminals 12 of acontrolling .device 15. Terminals of the field magnet windings 16, 17and 18 of the dynamo-electric machines are connected, respectively, tothe vertices of the delta-connected transformer windin s 9, 10 and 11that are opposite the wintings which are connected to the same pairs ofsupply circuit conductors as the armatures. The remaining terminals ofthe field magnet windings are connected, respectively, to stationarycontact strips 19 thatare disposed adjacent to the sets; of stationarycontact terminals 12. The controller 15 comprises further stationarycontact strips 22 that are arranged, respectively. in alinement with thestrips 19, suitable impedance devices 25, that preferably have the samepower factor as the field magnet windings us, 17 and 18, being connectedbetween the contact stri )S 19 and It also comprises three nrovab econducting members 28 that are insulated from each other and are adaptedto be moved over the respective sets of adjacent stationary contact:terminals and strips by means of an electro-magnet having a winding 29that is included in series with the supply circuit conductor (3.

The system may supply one or more suitable translating devices such asinduction motors 30, the amount of current required by which may varybetween -wide limits. The controller 15 is, therefore, so constructedand adjusted that the positions of the movablecondnctinp members 28 withrespect to the corresponding stationary contact strips and .tcrn'linalswill be determined by the amount of current required by the translatingdevices. Thus, when the load upon the I translating devices 30 is lightand the current traversing the winding 29 is comparatively small inamount, or less than a predetermined amount, the movable conductingpieces 28 will bear upon the stationary contact strips 22 and the lowerterminals 12, the field magnet windings 1(3, 17 and'lS being thenconnected to the transformer windings 9. 10 and 11 at such points as toapply electromotive forces thereto of such phases that the currents inthe armature circuits will be substantially in phase with electromotiveforces of the circuit t-56. The impedance devices 25 are also includedin circuit with the respective field magnet windings, the electromotiveforces applied to the field magnet windings being thereby so reduced inamount that. the counter-electron]otive forces of the armatures 1, 2 and3 will be less than the. electromotive forces of the circuit 5t5. Themachines will, therefore, op-

erate as motors and cause ener y to be stored in the fl v-wheel 8. Asthe End upon the translating devices 30 increases and the currenttraversing the winding 29 also increases, the movable conducting pieces28 are raised. thereby shifting the points of connection of the fieldmagnet windings with the-transformer windings 9, 10 and 11 in suchmanner that the currents in thearmatnre circuits are maintainedsubstantially in phase with the electromotive forcespf the distributingcircuit -l56 under all conditions of motor load. p

When the conducting pieces 28 enga e the stationary strips 19, \t eimpedance evices 23 are removed from the circuit, the field strengths ofthe dynamo-electric machines .being accordingly increased, and the 35machines are now caused to operate as gen-' erators, the energypreviously stored in the fly-wheel 8 being yielded and utilized as theactuating means for the machines. The points of connection of the fieldmagnet go windings 16, 17 and 18 with the transformer windings 9. 10 and11 are also'so adjusted when operating the machines as generators, thatthe electromotive forces generated by the armatnres'w-ill bear suchphase relations with respect to. the electromotive forces of the circuit456 as to cause the currents in the armature circuits to agreeapproximately in phase with the electromotive' forces of the circuit4-5-43 under substan- 10 tially all conditions of generator load.

It will, in general, be found that, in order to cause the currents inthe armature circuits to be in phase with the clec'tromotive forces ofthe distributing circuit 4-5----fi. the counter-electromotive forcesofthe arma tures. when the machines operate as motors. should lag behindthe electromotive forcesof the circuit 456, and the generatedelectromotive forces, when the machines operate as generators,shouldlead the electromotive forces of the circuit 456. These conditions willbe better understood from a consideration of the vector diagrams ofFigs. 4,5, 6 and 7 that illustrate the phase relations with respect toonly one of the machinesand in which E,, E and E, are the line voltages,or those of the circuit t5 6, E, representing the voltage of the circuitto which the armature-of the n'iacliine under consideration isconnected. I. is the electromotive force derived from the threephasetransformer and applied to the field circuit and it is the resultant ofone of the line clcctromotive forces. E. and an elcctromotive force inphase with that applied to the armature. or E,. It is also the resultantof electromotive forces IL, E, and E E, is the 'electromotive forceapplied to the field winding. 1,. is the electromotive force applied toan external ollmic resistance inserted in the field circuit whenoperating the machine as a generator in the systems of Figs. 2 and 3, tobe hereinafter described.

field Winding, elect-romotive forces E and E will agree in phase, and noshifting of the phase relations will be effected by .including theimpedance device in circuit with the field winding. It will, however, beunderstood that itis not essential, under all conditions, that the powerfactor of the impedance device be the same as that of the field winding,because the shifting of the phase relations that would otherwise resultmay readily be compensated for in theremainder of the system. E is thegenerated cl'ectromotive force when the machine operates as a generator,and the counter-electromotive force when the machine operates as amotor. L is the field current which is substantially 90 in phase behindthe field clectromotive force E because in practice the ohmic resistanceof the field winding is very low as compared with its inductiveresistance. The electro-motive force E is in phase withthc field currentL. I is the currentin the armature circuit. F ll represents theimpedance drop in the armature circuit. E,X is the resistance componentof the impedance drop, E,E and is in phase with the current I. It isopposed to,"and is overcome by, the line electromotive force,

'13,. when the machine operates as a motor,

ahd it is overcome by the generated electromotive force, E when themachine operates as a generator, so that it is then added to the lineelectromotive force, E,. E X is the inductive drop in thearmaturecircuit, or the inductive component of the impedance drop, E,Eand it is therefore 90 out of phase with the current I.

Figs. 4 and 5 represent the phase relations that exist when the machineoperates as a motor under different loads, as represented by thedifference in the lengths of the current vectors I, and also by theincrease in the impedance drop in the armature circuit, E,E If thereisno saturation of the magnetic circuits of the machine, the resistanceand inductive components of theimpedance drop will vary substantially in'noportion to the variations in the amount. of current I.

If, therefore, it. is desired to maintain the it in accordance withvariations in load. and

it is the purpose of the controller 15 otFig.

. 3 1, and one of theprime objects ofth e inv iii tion, to effectthisresult. It will b'eiunder stood'that, for motor operationunder-theconditions setforth, the conntenelectromotive force, E should belessthan'the-li electromotivc force, E and should lag l'fe hindit inphase, but for generator e em on it will be undcrstcmd, from an inspectit Figs. (3 and 7 which illustrate the phase-relations. existing- 1 underdifferent conditions ofgenerator load,that the generated electromotiveforce, E should begreater than the line electromotive f0rcc,-,E,,' andshould be ahead of it in phase, in order that. the/current I in thearmature circuit. mayl tlow against the line electromotive force l]; The

currents in the armature circuit are talten as of the same value inFigs. 4fa'nd (3 and also in Figs. 5 and 7, and the effect upon the phaserelations caused by changes in load and by changing from nmtor togenerator operation are clearly apparent. it being specially noted that,in the case of generator operation, as well as when the machine opcratesas a motor, the )hasc'ann'le bctn'ccn the electromotive force], I? and Eshould be adjusted in accordance with variations in load in order thatthe armature current. I. may always a ree in phase with thclince'lectrolnotive "orce 19,. This result clfected by means of thecontroller ol i l i In Fig. 2, three subdivided, auxiliaiy transformerwindings 31 are connected lactween the vertices of the delta-conn'ccli-dtransformer windings 9, 10 a nd ll. and in termediate points of therespective mjpt isilc windings, and the field-magnet wind-inns 1(3, 17and 18 are connected between jjdilfercnt. sets of points of the saidauxiliary windings in accordance with the 'varia ions in dhc may besimilar to theci'mtroller l5 of'l igrfl,

the stationary cont a ct terlninals of roan-011i; r?

32 being-connected to ithe several points of subdivision the auxiliarytransformer windings. By'this means, the elcctrmnotire forces applied tothe field magnctfwindings;

and,consequently, also the field strengtl' may bevar1edn accordance wtlrtlic var:

tions in the amount of currei'it required by' \the translating devlcesso that the -dyn'anm-= electric machines may be caused t-o --.hang 'cautomatically. from motors ,to generators;

and vice Versa, and also so that the field strengths may be correcti'orall condit ons of both motor .and,"generator 'loa,ds. Jln,

order to shittwthe ph generated clectroinotivc" tures with respect tothe elcctronmtivc for es of the circuit l-- ,-6. maintaining fthej.curi' circuits in pha.

for the purpose of,

fwitli the elcctromotive" forces of the circuit 4-5-6, under allconditions of load and whether operating the machines as motors orgenerators, resistances of varying amounts are included in eries withthe connections between the stationary contact terminals of thecontroller 32 and the points of subdivision of the auxiliary transformerwindings 31.. The effect upon the phase relations of the system ofintroducing the resistances 33 into the field circuits will bereadilyunderstood from an inspection of the vector diagrams of Figs. 4, 5, 6and 7.

In Fig. 3, the field magnet'windings 16, 17 and 18 are connected betweenthe vertices of the delta-connected transformer windings andintermediate points of the windings opposite, and for motor operationimpedance devices 34, referably of the same power factors as tie fieldwindings, are connected in series with the field windings for thepurpose of reducing the voltages applied to the said windings and,consequently, also the field strengths, the active lengths of thewindings of the impedance devices being adjusted in accordance with thevariations in the amount of current re quired by the translating devicesby means of a controller 35 that is similar in construction and mode ofoperation to those of Figs. 1 and 2. In order to shift the phases of theelectr'omotive forces applied to the field windings so as to cause thecurrents in the armature circuits to agree ap roximately in phase withthe elcctromotive orcesof the circuit 4-56, ohmic'resistance devices 36.

are included in series circuit with the field windings, the amounts ofresistance being increased in gradations as the amount of currentrequired by the translatin devices increases' Also, in order to providefor an increase of generator field strength as the current required bythe translating devices increases, gradually decreasing amountsofimpedance afforded by devices 37 are included in series circuit withthe field windings.

The invention may also be employed in connection with a twophase systemof distribution, such as that shown in Fig. 8, in

which mechanically coupled armatures 38 and 39, having large masses andconsiderable inertia, or a fly-wheel 40 coupled thereto, are connectedto the respective phases of a two-phase distributing circuit comprisingconductors 41, 42, and 44 that are supplied from a suitable source 45, aload for the system being provided as previously indicated, by means ofinduction motoI s or other suitable translating de ices 30. Field magnetwindings 46 and 47 of the dynamoelectric machines are connected to otherphases of the distributing circuit than those to which the correspondingarmatures are connected, so that electromot-lve forces are when theamount of current required b the translatin devices fallsbelow a preetermined vafue, the electromotive forces a plied to the field windingsare adjusted in phase with respect to the electromotive forces of thecircuit ,41424344, by including in the field circuits varying activelengths of transformer windings 48, upon which are impressedelectromotive forces of the same phases as those of the circuits towhich the corresponding armatures are connected. The active len he ofthe portions of the transformer win lugs included in the field circuitsare adjusted inaccordanoe with variations in the amount of currentrequired by the translating devices, by means of a controller 49 similarin construction and mode of operation to those previously described. Inorder, nlso, to reduce the electromotive forces applied to the fieldwindings for motor operation, impedance devices 13, of preferably thesame power factors as ed windings, are included in stries' the fi withthe field windings. For the purpose of causin ated by the armatures,when the machines are 0 )erated as generators, to lead in phase theelectromotive forces of the circuits to which the armatures areconnected, so that the currents in the armature. circuits may flowagainst the electromotive forces of the circuit 41424344, resistancedevices 50 are included in the field circuits, the amounts of resistancebeing adjusted in accordance with variations in the amount of currentrequired by the translating devices The field strengths, when operatingthe machines as generators, are caused to increase with increase of loadupon the system, by including gradually decreasing amounts of impedanceafforded by devices 13 in the field circuits.

The phase relations of the currents and electromotive forces in thesystem of Fig. 8 will be readily understood from 'an inspection of thevector diagrams of Figs. 9 and 10, Fig. 9 illustrating the relationsexisting when a single machine is operated as a motoreand Fig. 10illustrating the relations when the same machine is operated as agenerator. The reference characters employed in these diagrams have thesame signification as in Figs. 4, G and 7 with the addition of line 15,,which represents the electhe electromotive forces genertro'motive forceimpressed upon the field circuit by the transformer 48, thiselectromotive force being in phase with the electro motive force, E-,,'of the circuit to which the ter-electromotive force 15,, to lag behindthe electromotive force 11],, in order to obtain substantial phasecoincidence of the current I. with the electromotive force E,, for motoro ration. Tlie insertion of resistance in t efield circuit when.operating the ma.- chines as generators effects a. shifting of the phaseof-the electromotive force E; with re-. spect to the electromotive-forceE in the same manner as .has been previously d6" scribed.

' The invention may also be embodied in a sin le-phase system ofdistribution, such as is i lustr'ated in Fig. 11,.by providing'anexcitergenerator for the field magnet windi'ng 6-1 of thedynamo-electric-machii1e, the armature 62 of which is connected tosinglephase circuit conductors 63 and 64: and is mechanically coupled toa flywheel 65. The

field magnet winding 66 of the ex'citer gen Qrator'is supplied from thecircuit 6364, and F-the exciter is operated by means of. a motor 67 thatis also supplied from the cir- -.1cu;it"636l. As in the two-phase system(if Fi 8, varying amounts of resistance af- Yorde by a device 69areincluded' in series with the field winding61 for generator operation,and for motor operation varylng motive-lengths of a transformer winding70,

ire. included in'the field circuit, an electromotive forcebeing'impressed upon the winding 70- in, phase with that of the circuitEj3-64. The electromotive force applied to the fieldwinding, andconsequently the field.

fitrength also, is reduced for motor operation by including an impedancedevice 71, ofsub;

s'tantially the same power factor as that of the field winding, inseries with the field winding. It will be understood that the ct lect ofusing anexciter generator of the commutator type for supplyingv a field,winding issubstantially the same asconnecting the field winding to acircuit having an electromotive force 90 out of phase with the circuitto which the armature is connected as in the caseof the two-phasesystems previously described, since the electromotive force applied tothe field. winding of the exciter generator is substantially 90 outofphase'w-ith the electromotive force generated by the excite]: armature.It is,

therefore, unnecessary to describe the phase relations existing in thesystem of Fig. 11.

As here shown, the ratio of the electromotive iorces of the arniaturesof'the machines to the electromotive forces of the distributing circuitis adjusted by varying the field. strengths of the machines, but this result may be secured in any other desired of the invention oraltering itsmode of operation, and many other modifications of the systems hereinset forth may also be made within the scope of the inventi on.

I claim as my invention:

1." The combination with an alternating current distributing circuit,and a dynamoelectric machine adapted to operate either as a motor or asa generator and having its armature connected to said circuit, of meansfor applying an electromotive force to the field magnet winding, andmeans for adjustmg the phase of said electromotive force in accordancewith the variations in the amount of current required from thedistributing circuit.

2. The combination with an alternating current distributing circuit, anda dynamoelectric'machine adapted to operate either as a motor or as agenerator and havingit's armature connected to said circuit, of meansfor applying an electromotive force to the field magnet winding of themachine, and means'for adjusting both the phase and value of the saidelectromotive force in accordance with the variations in the amount ofcurrent required from the distributing phase with the electromotiveforce of the distributing circuit, whether the machine operates as amotor or as a generator and under substantially allconditions of currentload.

4. The combination with an alternating current distributing circuit, anda dynamoelectric machine connected thereto, of means for adjusting thefield strength of the machine to cause it to operate as a motor when thecurrent required from the distributing circuit is less than apredetermined amount, and to operate as a generator when the saidcurrent is greater than the predetermined amount, and means foradjusting the phase of the electromotive force applied to the fieldmagnet winding.

The combination with an alternating current distributing circuit, and adynamoelectric machine connected thereto, of means for causing motorwhen d lstributi n g the machine to operate as a i termined amount andto operate as a generator when the said current exceeds thepredetermined amount, and means for adpisting-the phase of theelectromotive force applied to the field magnet winding.

6. The combination with an alternating current distributing circuit, anda dynamoelectric machine connected thereto, of means for causing themachine to operate as a motor when the current required from thedistributing circuit is less than a predetermined amount, and to operateas a generator when the said current exceeds the predetermined amount,and means for causing the current in the armature circuit to agreeapproximatel in phase with t-lIQ QlQCtIOIIIOYIYQ force of thedistributing circuit.

t current distributing circuit. and a dynamoelectric machine connectedthereto, of means for adjusting the field strength of the machine tocause it to operate as a motor when the current required from thedistributing circuit ltSH than a predetermined amount, and to operate asa generator when the said current is greater than the predeterminedamount; and for adjusting the phase of the elec romotive force appliedto the field magnet winding to cause the current in the armature circuittoagree approximately in phase with the electromotive force of thedistributing circuit.

8. The combination with an alternatingcurrent distributing circuit, anda dynamo-electric machine connected thereto and adapted to operateeither as a motor or as a generator, of means for causing thecounter-electromotive force of the machine, when oper ating as a motor,to lag behind the electromotire force of the distributing circuit, andthe electromotive forcc generated by the ma chine, when operating as agenerator. to lead theelectromotive force of the distribut ing circuit.

5). The combination with an alternating current distributing circuit,and a dynamoelectric machine connected thereto and adapted to operateeither as a. motor or as a generator, of means for adjusting the phaseof the electromotive force applied to the field magnet winding of themachine to cause the counter-electromotive force of the machine, whenoperating as a motor, to lag behind the clectromotive force of thedistributing circuit, and the electromotive force generated by themachine, when operating as a generator, to lead the electromotive forceof the distributing circuit.

10. The combination with an alternating current distributing circuit,and a dynamoelcctric machine connected thereto adapted to operate eitheras a motor or as a generator, of means. for adjusting the field strengthof the machine to cause it to operate as a motor when the currentrequired from the distributing circuit is less than a pre- Thecombination with an alternating.

and

determined amount and to operate as a enerator when the said current isgreater t tan the predetermined amount, and means for adjusting thephase of the electromotive force applied to the field magnet winding tocause the counter electromotive force of the machine, when operating asa motor, to lag behind the electromotive force of the distributingcircuit and the electromotive force generated by the machine, whenoperating as a generator, to lead the electromotive force of thedistributing circuit.

11. The combination with an alternating current distributing circuit,and a dynamoelectric machine connected thereto and adapted to operateeither as a motor or as a generator. of means for causing the machine tooperate as a motor when the current recuired from the distributingcircuit is less t tan a predetermined amount and to operate as agenerator when the said current is greater than the predeterminedamount, and means for adjusting the phase of the electromotive force apilied to the field magnet winding to cause he counter electromotiveforce of the machine, when operating as a motor, to lag behind theelectromotive force of the distributing circuit, and the electromotivcforce gene 'ated by the machine, when operating as a generator, to leadthe electromotire force of the distributing circuit.

12. The combination with -an alternating .current distributing circuit,and a dynamoelectric machine connected thereto, of means for adjustingthe ratio of the voltage applied to the field magnet winding withrespect to that of said circuit to cause the machine to operate eitheras a generator or as a motor, according as the current rcquircd of thedistributing circuit exceeds or is less than a pret'letermined amount,and means for causing the machine to receive current from, or to delivercurrent to, tho distributingcircitit of substantially thesame phase asthat of the distributing circuit.

13. The combination with an alternating current distributing circuit,and a dynamo electric. machine connected thereto and adapted to operateeither as a motor or as a generator, of a variable ohmic resistance anda variable reactance in the circuit of the field magnet winding of themachine.

14. The. combination with an alternating current distriituiting circuitand a dynamoelectric machine connected thereto and 4 adapted to operateeither as a motor or as a generator, of a reactance device and an ohmicresistance device in the field circuit of the machine, andmeansgoverning the amounts of resistance and reactance included in the fieldcircuit that is responsive in operation to the variations in the amountof current required from the distributing circuit.

e 15. The combination with an alternating current distributing circuit,and a dynamoelectrlcmachine connected thereto 'and adaptedjto operateeither as a motor or as'a generator, of means for causing thecounterelectl'omotire force of the machine, when operating as a motor,to lag behind the electromotive force of the distributing circuit. andthe electromotire force generated by the machine, when operating as agene 'ator, to lead the electromotive force of the distributing circuit,and an impedance device included in the field circuit when the machineis operating as a motor. 7

16. The combination with an alternating current distributing circuit,and a dynamoelectric .machine connected thereto and adapted to operateeither as a motor or as a generator, of an ohmic resistance included inthe field circuit of the machine when the' same is operating as agenerator, and means for reducing the field strength of the machine whenthe same is operating as a motor.

17. The combination with a polyphase alternating current distributingcircuit, and a plurality ofmechanically coupled dynamoelectric machineshaving their armatures associated, respectively, with different phasesof said circuit and their field magnet windings associated with otherphases of said circuit than those with which the corresponding armaturesare associated, of means for adjusting the field strengths of themachines to cause them to operate as motors when the current required ofthe distributing circuit is less than a predetermined amount, and tooperate as generators when the said current is greater than thepredetermined amount, and means for adjusting the phases of theelectromotive forces applied to the field magnet windings.

18. The combination with a polyphase alternating current distributingcircuit, and a plurality of mechanically coupled dynamoelectric machineshaving their armatures as sociated, respectively, with different phasesof said circuit and their field magnet windings associated with otherphases of said circuit than those with which the corresponding armaturesare associated, of means for causing the machines to operate as motorswhen the current required from the distributing circuit is less than apredetermined amount, and to operate as generators when the said currentis greater than the predetermined amount, and means for adjusting thephases of the electromotive forces applied to the field magnet windings.

19. The combination with a polyphase alternating current distributingcircuit, and a plurality of mechanically coupled dynamoelectric machineshaving their armatures associated, respectively, with different phasesof said circuit and their field magnet wind in associated with otherphases ofv the circult thanthose with which the correspondmg arn'iatm-esare HSSOCldtQd, of means for" adjusting the field strengths of themachines to cause them tooperate as motors when the current required ofthe distributing circuit is less than a prede'tcrminetl amount, and tooperate as generators when the said current is'greater than thepredetermined amount, and means for adjusting the phases of theelectromotive forces applied to the field magnet windings to cause thecurrents in the armature c-ir'cuits to agree approximately in phase withthe electromotive forces of the distributing circuit.

20. The combination with a polyphase alternating current distributingcircuit and a plurality of mechanically coupled dynamoelectricn'iachines having their armatures connected respectively to differentpairs of conductors thereof, of three delta-connected transformerwindings connected to the distributing circuit, the field anagnetwindings of the machines being supplied with currents derived fromcircuits extending between the intermediate points of the transforn'ierwindings that are connected to the same circuit conductors as thecorresponding arn'latures of the machines and the connections betweenthe other two transformer windings, and means for adjusting the phasesof the electromotive forces applied to the field. magnet windings tocause the currents in the armature circuits of the machines to agreeapproximately in phase with the electromot1\-'e forces ofthe-distributing circuit.

21. The combination with a polyphase alternating current distributingcircuit and a plurality of mechanically coupled dynamoelectric machineshaving their armatures connected respectively to difi'erent pairs ofconductors thereof, of three delta-connected transformer windingsconnected to the distributing circuit, the field magnet windings of themachines being supplied with currents derived from circuits extendingbetween the intermediate points of the trans former windings that areconnected to the same circuit conductors as the corresponding armaturesof the machines and the connections between the other two transformerwindings, and means for adjusting both the phases and values of theelectromotive forces substantially all conditions of current load.

22. The combination with an alternating current distributing circuit,and a dynamofcircuit, and the electromotive force electric machineconnected thereto, of means for causing the machine to operate as amotor when the current required of the distributing circuit is less thana predetermined amount and as a generator when the said current (isgreater than the predetermined amount, and means for causing the countereleetroinotive force of the machine, when operating as a motor, to lagbehind the electromotive force of the distributing enerated by themachine, when operating is a generator, to lead the electromotive forceof the distributing circuit.

In testimony whereof, I have hereunto subscribed in name this 24th dayof August, 1907.

\VILLIAM COOPER. Witnesses:

l'lowann L. BEACH, BIRXEY IIINES.

